The broad, long-term objective of this proposal is to evaluate ethnic differences in the incidence and antecedents of diabetic complications in a large, well-characterized population of African Americans, Asians, Caucasians, Filipinos, and Latinos within an integrated, managed care setting Kaiser Permanente (KP). The study will focus on health services and epidemiologic aspects of diabetic complications including myocardial infarction, stroke, congestive heart failure, end-stage renal disease, lower-extremity amputation and proliferative retinopathy. Disparities in the complications of diabetes are well documented. This investigator previously reported findings of ethnic disparities, but with inconsistent patterns, in rates of complications among diabetic members of KP, despite uniform health coverage (Appendix A). The next step will be to identify modifiable factors that differ by ethnicity and may therefore help to explain observed disparities. If such risk factors differ either in prevalence and/or effect size across ethnic groups, they may explain a portion of the ethnic disparities and inconsistent patterns of rates of complications. We propose to survey and prospectively follow approximately 20,000 diabetic patients, with equal representation from the 5 largest ethnic groups, to collect a rich source of information regarding potentially explanatory, modifiable risk factors (clinical, socioeconomic, behavioral, psychosocial). These factors could serve as appropriate targets for interventions aiming to reduce ethnic disparities in complications. Secondary aims include evaluating ethnic differences in i) the association between the quality of the patient-provider relationship and patient adherence; ii) access to appropriate specialty care and rates of standard processes of care; iii) the incidence of complications among smaller, rarely studied ethnic groups (Native Americans, Pacific Islanders and South Asians); and iv) rates of diffusion of newly introduced preventive health innovations. Secondary aims 5 and 6 will be based on a pre-existing cohort in an ongoing longitudinal study of approximately 78,000 respondents to a survey initiated in 1994 (83% response rate). By studying a population with uniform health coverage, this study will complement extant national surveillance and population-based studies that include patients with varying levels of medical coverage. These latter studies are less able to disentangle the confounding effect of ethnic disparities in health care access and quality. Further characterizing ethnic disparities in the incidence of complications in a contemporary, insured population with diabetes and identifying key modifiable factors that can be the focus of targeted interventions will have public health and scientific value.